The art has long recognized the need to provide covers for railroad cars that are open at the top, so as to protect the materials carried in the interior of the railroad car from damage caused by elements or other external sources. In particular, materials such as coal and similar fuel sources, as well as food stuffs and other perishable materials should be covered, principally to avoid damage caused by water entering the railroad car interior.
Desirably, railroad cars carrying material in bulk should be open at the top, so as to provide an easy means of loading cargo through a hopper which is suspended over the top of the railroad car, and unloading cargo through the simple expedient of tipping the railroad car on its side, or otherwise scooping the material out by use of a crane or similar apparatus. However, such openings are necessarily directly exposed to the weather. Accordingly, railroad cars in the prior art have frequently been provided with heavy covers made with steel or similar material, which necessitated complex and difficult removal prior to loading and unloading.
The same covers due to their weight, substantially increased transportation costs in terms of the amount of fuel that must be consumed to transport the same amount of material an equivalent distance as that consumed with an uncovered railroad car. Further, the same covers often presented a wide face to the wind created by the railroad cars passage, such that wind resistance caused a "lifting effect" requiring bulky, heavy means of attachment to the railroad car itself. This wind resistance also further increased transportation costs by increasing equivalent fuel consumption.
Accordingly, it is one object of this invention to provide a light-weight railroad cover that may simply and easily be opened so as to allow loading of the railroad car from above, and unloading through the top or open end of the railroad car.
A second object of this invention is to provide a railroad car cover which is light-weight, yet strong enough to meet the demands placed upon such covers, while providing a weather-and-water tight protection for the material within the railroad car.
Yet a further object of this invention is a railroad car cover which, because of its structural design, provides a reduced lift while in motion, thereby eliminating the need for heavy attachments or alternative means of securing the cover to the top of the railroad car.
Further objects of this invention will be apparent from its description below.